Marko Milovanovic on behalf of ATLAS Forward Detectors ... · AFP status & LS2 plans (LHC-XAFP-EC-0005) > SiT Refurbishment: Module production (UBM, dicing, bump-bonding, mounting,

ATLAS FWD LS2 scheduleTREX meeting #22

Marko Milovanovic

on behalf of ATLAS Forward Detectors

CERN, 17.04.2019

Marko Milovanovic | TREX meeting #22 | 17 April 2019 | Page 2

ALFA LS2 shielding issue

> The survey team (Jean-Frederic Fuchs et. al.)

suggested a solution during the ‘Reunion ICL

Machine LHC et SPS’ meeting on 16.01.2019:

https://indico.cern.ch/event/787563/

> Sector Q5-Q6: Two blocks of the wall must be dismounted.

Review of the lower block design.

> Sector Q6-Q7: 8 shielding blocks can stay in place.

a specific process (using a stretched wire) will

be used to align the both XRPA components.

will take more time than standard; EN-CV

cooperation needed to reduce ventilation.

> Two possible solutions for Q5-Q6 wall:

Return the blocks after the final survey before Run3

Modify the shielding so no further intervention needed.

> For this reason, we requested:

Readout of installed Machine NMOS dosimeters

(RadMons) to compare with our own TLD100s

New FLUKA simulation of radiation damage with the

shielding lowered down by 80cm (2 blocks removed)Sector Q5-Q6 Sector Q6-Q7

https://mmm.cern.ch/owa/redir.aspx?C=Ix8jZz5SntlafOn_YhWl1bkF62gE7eWxujmEcae9SGS3uubZdnzWCA..&URL=https://indico.cern.ch/event/787563/


ALFA LS2 shielding issue

> We got all the results only last week, showing:

RadMon data indicate a maximum dose acquired in

2018 of around 20 Gy (50% uncertainty due to Sv-to-Gy

conversion) (https://edms.cern.ch/document/2137118/1)

FLUKA simulations show a damage increase of ~50% in

the FAR (B) stations of ALFA electronics, and only a

minor increase in NEAR (A) stations if the 2 blocks

(80cm) are removed (ToF detector included).

(https://cernbox.cern.ch/index.php/s/hCRHLs2CcjOI7Vt)

> Conclusions:

Based on the dose limit (250 Gy) for proper function of

ALFA electronics, as well as luminosity prospects in

Run3, partial shielding removal is acceptable, but still

quite considerable. Therefore, a compromise solution:

Request a replacement of the top two blocks of Q5-Q6

walls by a total of 35 cm high block arrangement, thus

reducing it by 45cm effectively and enabling survey.

Request ALFA special runs in Run3 to be as early as

possible (although for ALFA elastics run at 14TeV it

would be 2022(?) and for diffraction even afterwards…)

> ECR (LHC-JS-EC-0001-rev1-5) updated and

submitted for approval.

> 2 top blocks in each of zone Q5-Q6 walls will

be removed in May 2019.

https://edms.cern.ch/document/2137118/1

https://cernbox.cern.ch/index.php/s/hCRHLs2CcjOI7Vt


ALFA status & LS2 plans

> Spare MB production:

Radiation damage assessment for MBs and fibers: ~10x below dose limits, however due to LHC

water leak, we have no more spares! Production of 4-8 new MBs (Bruno, EP-ESE-FE). Should

be produced by end of 2019.

> Movement, vacuum & ventilation systems:

Strong support provided by EP-DT-DI.

Preventive replacement of all HOME switch optocouplers (end of LS2).

Replacement of cooling fans’ bearings (Spring 2019) to allow for monthly full system tests.

Installation of radiation hard and custom made flowmeters (end of 2019).

Vacuum system pump diaphragms to be replaced at the end of LS2.

DCS improvements (hardware and software) to shorten transition times (2019-2020).

Full system movements tests pending due to an issue/difference in Motor and LVDT readout

(~750/100 μm in lower RP6/8 detectors); found malfunctioning end-switches & stoppers, which

will be replaced by the end of LS2. Necessary to do perform all activity before the survey!

> Online monitoring software improvements & collimation

Request from LPC to improve online monitoring to allow quicker/better estimation of signal/BG.

Offline analysis showed the crystal collimation scheme data can be used regardless of 3x higher

background (1.5% in comparison to 0.5%). Now well understood where the increased

background comes from; easily mitigated with an additional TCLA (A5R3.B2) setting.


AFP status & LS2 plans (LHC-XAFP-EC-0005)

> SiT Refurbishment:

Module production (UBM, dicing, bump-bonding, mounting, wire-bonding etc.) to start latest in

October. Modules should be ready for installation and commissioning by Spring 2020. Extraction

and re-installation of all SiT detector packages scheduled for mid 2020.

> Time-of-Flight detector:

Critical issue: operating MCP-PMT at ~2kV in vacuum. Two solutions being tested:

Improve HV insulation of PMT: pot ‘bare’ PMTs ourselves (long term tests ongoing; 4 [email protected] ok)

Mount PMT outside vacuum - do light reception through Q window; modified flange is being produced.

So far, ATLAS is in favor of the baseline/potting solution. If successful in the next 2 months (2

more PMTs), will give a green light for Installation in mid 2020.

> Cooling system:

Cooling will have to be improved for Run3 (2x higher beam intensity) in the FAR stations.

Considering to install radiators+temperature sensors on the flange with fans together w/ToF.

Adding automatic valves for main pressure adjustment - mid 2020.

> Movement system & PXI/FESA Upgrade

FESA/PXI Upgrade: AFP only since more expensive for ALFA and having better prospects for

Run4 (total cost: ~19kchf). ALFA will have spares from AFP. Should commence mid-2019.

> All interventions touching the beam-pipe elements should be concluded until Summer 2020! Survey,

alignment, movement calibration and commissioning for both ALFA & AFP until end of 2020 (W29-

42). Survey takes ~1 day per station (2 weeks total for ARP).


LUCID status & LS2 plans

> Despite 19/32 of PMT channels stopped working in

2018, LUCID provided the most precise luminosity

determination.

> The cause of the malfunctioning PMT channels is

being investigated. The channels are typically not

100% dead but unstable at high luminosity, which

makes finding the cause very difficult

> Tests on 7 PMTs removed in YETS 2017 and 1

PMT+Base removed at the beginning of February

has already started in Bldg.180.

> Two modules are transported to storage in

Prevessin for radiation cooling down until

September and then bring them back to SX1. A

test stand will be made to connect all channels to

HV and read them all out.

> Radiation resistance tests (n and g): summer 2019

> The rest of the planning will depend on the

understanding of the cause of the problem.

> Detector refurbishment in 2020.

by Vincent Hedberg


ZDC Status & LS2 Plans

> Removal of 2018 ZDC:

RP concerns (activation of TAN & nearby collimators) requires

waiting until May 2019. Need to clarify RP issues near TAN to

understand boundary conditions on ZDC de/installation.

Plan to schedule removal during first week of June 2019.

> R&D and construction of Run 3 ZDC:

Higher luminosity & event rates require updates to active material

(currently quartz) & readout (currently L1Calo).

R&D collaboration with CMS (& possibly LHCb in future). Reduced

transverse size to fit in the new TAN (Phase II). Plan to use fused

silica rods -> much more radiation hard.

Planning upgrade to trigger and readout chain, based on modified

LUCROD (320/480 MHz sampling vs. 40/80 MHz).

Signal transmission to be improved by use of air-core cables.

Running with LHCf in RUN3

No compromises to be made on construction or installation.

Having two complete ZDCs in the O+O run (2022) takes priority.

In p+O run, only one LHCf detector to be assumed.

> Calibration of Run 2 data:

Ongoing efforts to optimize reconstruction and calibration of

2015, 2016, 2018. Completion probably in late 2020.

by Peter Steinberg

Main uses for ZDC in Pb+Pb:

Triggering: distinguishing

minimum-bias (2 arm) from EM

processes (0,1 arm).

Event-selection, pileup rejection.

LUCROD


Backup

Backup slides.


ZDC/LHCf in Run3

> In 2013 and 2016, LHCf replaced segmented EM modules

> In late February, ZDC & FD PL met with LHCf

> They want two short runs, involving ZDC

Short low-µ run at start of Run 3 (2021): new energy, higher rate

Request for ZDC hadronic modules behind LHCf to improve n

energy measurement (30-40% with 1.5λ)

Need to have detailed plan in advance

Which detector/readout can be used in early 2021? Current plans imply old

ZDC/electronics

ZDC installation and deinstallation schedule given new RP issues

Calibration procedure for pp

What if 14 TeV not achieveable? Is high rate 13 TeV data still interesting?

Short p+O run in 2022 for cosmic ray physics: well-motivated

LHCf physics

If during HI running, then will displace either/both ZDC EM

module(s)

Issues: can LHCf be removed quickly so ZDC has 4 modules during

HI runs?

Point for discussion: Could ZDC utilize scintillating tile readout and

use LHCf as EM module in 2022?

by Peter Steinberg


ARP LS2 schedule


Initial AFP LS2 schedule


AFP ECR draft schedule


LSS1L access constraints


LSS1R access constraints


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Backup - AFP

SiTToF

AFP station

ALFA – Beam ViewAFP – Beam View

Single Diffraction @ Standard Optics Elastics @ β*=2.5 km Optics


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Documents

Marko Milovanovic on behalf of ATLAS Forward Detectors ... · AFP status & LS2 plans (LHC-XAFP-EC-0005) > SiT Refurbishment: Module production (UBM, dicing, bump-bonding, mounting,